问要求T_FUNCTION的php后期静态绑定恢复错误

EN

abstract class father {
    protected $lastname="";
    protected $gender="";

    function __construct($sLastName){
        $this->lastname = $sLastName;
    }

    abstract function getFullName();

    public static function create($sFirstName,$sLastName){
        return new self($sFirstName,$sLastName);
    };
}

class boy extends father{
    protected $firstname="";

    function __construct($sFirstName,$sLastName){
        parent::__construct($sLastName);
        $this->firstname = $sFirstName;
    }

    function getFullName(){
        return("Mr. ".$this->firstname." ".$this->lastname."<br />");
    }
}

class girl extends father{
    protected $firstname="";

    function __construct($sFirstName,$sLastName){
        parent::__construct($sLastName);
        $this->firstname = $sFirstName;
    }

    function getFullName(){
        return("Ms. ".$this->firstname." ".$this->lastname."<br />");
    }

}


$oBoy = boy::create("John", "Doe");
print($oBoy->getFullName());